Static 3D images are conventionally produced by obtaining raw 3D data, e.g., data on a coordinate system (x, y, z), through a 3D probe regardless of acquisition time, by stacking frames over one another at a uniform time interval to form consecutive frames, and by processing the consecutive frames using a 3D rendering technique. Where static 3D images are used for ultrasound diagnostic purposes, one may easily make accurate observation, diagnosis, or treatment of the internal state of a human body without performing complicated procedures associated with invasive operations. Thus, static 3D images are widely used. However, static 3D images are not useful in observing a moving target object in real time, such as an embryo in the uterus.
In order to overcome this shortcoming, a live 3D imaging method and apparatus for providing a 3D moving image, rather than static 3D images, has been developed. Herein, a live 3D image should be understood and interpreted as a quasi real-time 3D moving image, representing movement of a moving target object. The live 3D image consists of fewer frames than those of a real-time 3D moving image so that it does not completely represent movement of a moving target object. However, since the live 3D image consists of more frames than static 3D images, e.g., 2 to 4 frames per second, it can represent movement of a moving target object more smoothly than the static 3D images.
Referring to FIG. 1, which illustrates a schematic block diagram of a conventional ultrasound apparatus for producing a live 3D image, live 3D imaging apparatus 100 comprises probe 102 for transmitting and receiving ultrasound signals to/from a moving target object (not shown), i.e., scanning the moving target object; image processing unit 104 for producing a live 3D image by using the reflected ultrasound signals transmitted from probe 102; and display unit 106 for displaying the live 3D image produced by image processor 104.
Image processing unit 104 includes raw 3D data obtaining unit 108 and rendering unit 110. Raw 3D data obtaining unit 108 obtains raw data required for producing the live 3D image based on the reflected ultrasound signals transmitted from probe 102, which are transmitted to rendering unit 110. (Hereinafter, raw data refers to raw 3D data) Raw 3D data obtaining unit 108 may sequentially store raw 3D data corresponding to each frame on a predetermined storage unit (not shown), which are transmitted to rendering unit 110. Rendering unit 110 then performs a conventional rendering process on the raw 3D data transmitted from raw 3D data obtaining unit 108 and produces the live 3D image to be displayed on display unit 106.
Referring to FIG. 2, which shows a flow chart for conventionally producing a live 3D image, probe 102 scans a moving target object by transmitting ultrasound signals to the moving target object and receiving the ultrasound signals reflected therefrom (Step S202). Raw 3D data obtaining unit 108 of image processing unit 104 obtains raw 3D data and stores them on a predetermined storage unit (Step S204). Where the stored raw 3D data correspond to n number of frames, rendering unit 110 reads raw 3D data corresponding to the (n−1)th frame among n number of the frames, which is stored just before the nth frame, and performs a high-speed rendering on the (n−2)th frame, which is stored just before the (n−1)th frame (Step S206). By performing such parallel rendering processes repetitively, rendering unit 110 performs live 3D imaging to produce the live 3D image of the moving target object. Display unit 106 displays the live 3D image thereon (Step S208). The frame rate of the live 3D image displayed on display unit 106 is typically 2 to 4 frames/second.
As described above, with conventional live 3D imaging apparatus 100, displaying images like a cinema is very difficult, since the live 3D image consists of 2 to 4 frames per second while the cinema typically consists of at least 30 frames per second. For example, if a frame rate of the live 3D image is 4 frames per second, the live 3D image may be discontinuously displayed for one second.
Thus, need exists for an apparatus and method for providing a natural looking 3D moving image by raising the conventional frame rate of live 3D image without increasing the calculation load of an live 3D imaging apparatus.